1. Field of the Invention
This invention relates to indexing heads for use with machine tools, for example, erosion machines and fine grinders, and horizontal jig boring mills, in, for instance, the supermachining of workpieces.
2. Description of the Prior Art
There are known many indexing heads received by the spindle and carrying the tool, for the adjustment on all sides of workpieces on machine tools. As a rule, the known indexing heads have a graduation at a peripheral surface of a rotatable disc, and a counter-marking associated with a stationary disc, there being also optionally provided a so-called Vernier scale for fine setting. Such a form of graduation is, even in combination with a Vernier scale, no longer adequate for the accuracies required at the present time, in many cases the degree of accuracy required being to arc minutes and seconds.
Indexing heads are known from U.S. Pat Nos. 3,049,032, 2,177,006 and 2,342,539, Swiss Pat. No. 542,687 and German Offenlegungsschriften Nos. 2,109,270 and 1,427,085. These known heads have the defect of extremely inconvenient construction, and they afford only relatively coarse setting or the setting or adjusting means are inconvenient to manipulate.